The present invention relates to a solenoid clutch which minimizes the noise generated by armature movement by damping the impact armature contacting the rotor.
Conventional solenoid clutches employ the following construction. An armature hub has apertures or holes in a flange portion. A damper cover having apertures communicating with the apertures of the armature is fixed to a flange portion of the armature hub. Each damper rubber piece has an aperture at the center that is accommodated in the damper cover. A collar has a flange portion which comes into contact with the outside surface of the damper rubber portion. The collar is fitted into the apertures of the damper rubber portion as well as the apertures of the flange portion of the damper rubber portion and the damper cover-armature hub. While the end face of the collar is brought into contact with the armature superposed with the flange portion of the armature hub, the armature and the collar are integrally fixed to one another by rivets (see Japanese Utility Model Publication No. 8997/1983). A torque transmission pin is formed by the collar and the rivets in the conventional solenoid clutch.
In the solenoid clutches having the construction described above, the armature is magnetically attracted to the rotor while compressing the damper rubber portion by the flange portion of the collar. The attraction force is caused by means of the magnetic flux which is generated when a current is supplied to a solenoid coil. When the supply of the current to the solenoid coil is removed, the magnetic flux collapses, so that the armature is separated from the rotor by the damper rubber.
In conventional solenoid clutches, noise is generated from the impact of the armature as it is attracted to the rotor. The present invention is directed to prevent the occurrence of the armature attraction sound by mitigating the impact.